This is overly complex. The initial setting of env var EVR at the beginning of
the script does nothing, and the C program is just using the environment to
store a temp value, which isn't even needed. The usage of a file is also
unnecessary (unless you want to retain the value).
This would do the same thing...
#!/bin/sh
EVR=`./your_c_program`
Or in csh
#!/bin/csh
setenv EVR `./your_c_program`
With the C program being
printf("%d", int_value);
or
printf(string_value);
or whatever needs to be set in the env var.
- Rob
> -----Original Message-----
> From:
> [email protected]
> p.com
> [mailto:[email protected]
> avincidsp.com] On Behalf Of Sander Huijsen
> Sent: Thursday, December 18, 2008 6:08 AM
> To: [email protected]
> Subject: RE: A way to export from c an environment var
>
> Well yes, Arie, you are right about that. I did find a
> clever/nasty (you be the judge of that) solution for the
> problem. Simply write the environment variable from within
> your application to a file, and then "source" the file in
> your script. :-)
>
> The script might look something like this:
>
> [script]
> #!/bin/sh
>
> # create some environment variable 'EVR' and show it
> EVR="your value"
> echo $EVR
>
> # run your C program, which changes EVR and exports it
> to /tmp/evr.env
> ./your_c_program
>
> # source the changed environment
> source /tmp/evr.env
>
> # now show the changed value
> echo $EVR
>
> # and exit the script.
> exit 0
> [/script]
>
>
> In your C program, you would do something like this:
>
> [snippet]
> // Here, you change the environment variable
> setenv("EVR", "my changed value", 1);
>
> // Open a temp file to write the environment variable in
> FILE *fh = fopen("/tmp/evr.env", "w+");
> if (fh)
> {
> // This will write 'EVR="my changed value"' in
> the temp file
> fprintf(fh, "EVR=\"%s\"\n", getenv("EVR"));
> fclose(fh);
> }
> [/snippet]
>
>
> Regards,
> Sander
>
>
> -----Original Message-----
> From: Arie de Muijnck [mailto:[email protected]]
> Sent: Thursday, December 18, 2008 10:52 AM
> To: Sander Huijsen; [email protected]
> Subject: Re: A way to export from c an environment var
>
> Unless one wants to set a persistant value, that can be used
> after his/hers process finishes...
>
> Unfortunately functions like setenv(), putenv(),
> system("export ...") change only the current environment of
> the process itself, not the 'global'
> environment of the user (let alone the system).
>
> Regards,
> Arie de Muijnck
>
> ----- Original Message -----
> > You might want to try setenv(). Just type 'man 3 setenv' in a Linux
> > shell to get the man-page for that function (which is in stdlib).
> >
> > Sander
> >
> >
> > -----Original Message-----
> > Hi,
> >
> > Is there a way to create and export from c an environment
> variable a
> > bash script can be aware of? I intend something like PATH, etc.
> >
> > Thanks and Regards,
> >
> > VanVliet
> >
> > Dr. Caroline Van Vliet
> > Adfl Group
> > Advanced DSP Flexible Language Group
> > Via Greto di Cornigliano 6R
> > 16152 - Genova, Italy
> > Tel. +39 010 8609370 - Fax +39 010 8609381
>
> --------------------------------------------------------
>
>
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